The present invention relates to an ignition system, especially to a contactless capacitor discharge type ignition system for an internal combustion engine, in which a magneto generator is employed as an electric power source for charging a capacitor provided therein, and more especially to an ignition system which prevents particularly a two-cycle engine from being continued to rotate in a reverse direction.
In a conventional ignition system of this kind, it is known that continuation of reverse rotation of an engine is prevented by preventing the system from supplying an ignition signal to a control gate of a switching element such as a thyristor; however when the engine is forced to rotate in the reverse direction at a high speed due to some accidental reasons the capacitor is charged by higher voltage produced at the magneto generator, and thereby such electric elements as the capacitor, thyristor, a diode or the like may be broken because of such high voltage.